Micro-Universal Serial Bus (USB) connections have become increasingly common. With the increased popularity, the micro-USB ports have been adapted to perform high-speed data transfers and low-speed data transfers, operating as an audio output ports, video ports, battery charging ports, and so forth. Performing this variety of tasks generally requires the use of a multi-port switch. This switch, though, can have a large impedance (about 5Ω) compared to the typical USB terminal impedance of 45Ω. This impedance can seriously degrade the transmitter or output voltage swing at the USB port, which is generally required to have a peak-to-peak (differential) swing of 800 mV with a common mode of 200 mV at a speed of about 480 Mb/s.
Some examples of conventional circuits are U.S. Pat. Nos. 6,141,719; 7,039,731; 7,484,018; U.S. Patent Pre-Grant Publ. No. 2008/0297265; U.S. Patent Pre-Grant Publ. No. 2009/0002085; and U.S. Patent Pre-Grant Publ. No. 2009/0029733.